In recent years, an ultrasonic imaging device endowed with a three-dimensional imaging function is rapidly shifting to a phase of commercialization and clinical application. Such an ultrasonic imaging device endowed with the three-dimensional imaging function employs a probe which incorporates a large number of transducer elements, for example, around a few thousands of elements. Therefore, it is necessary to bundle output signals in units of multiple transducer elements, and to reduce the number of signals, down to the number from 100 to 200, which corresponds to the number of I/O channels of the imaging device main unit.
Patent document 1 discloses a configuration that a phasing circuit is divided into two stages; storing in a probe, a sub-focusing circuit in which multiple transducer elements are bound into one sub-channel, and storing in the device main unit, a main-focusing circuit in which multiple sub-channels are bound into one channel. With the configuration, the sub-channel shape and the channel shape are dynamically controlled, and a width of the transducer elements, which are bound into the same channel, is made to be the same as the distribution width of one transducer element, irrespective of a deflective direction, whereby deterioration of beams can be suppressed.
Patent document 2 discloses a configuration that the two-dimensional array transducer elements 20 are divided into multiple concentric ring areas about a perpendicular line dropped from a wave transmission or wave receiving focal point, and a group of transducer elements within a concentric ring area are connected to one signal line (see FIG. 2 of the patent document 2). The group of transducer elements within the ring area has an approximately the same distance from the focal point, and receiving signals of each transducer element are approximately in phase. Signals in phase do not cancel one another out even though they are added together. Therefore, according to the configuration as disclosed in the patent document 2, a group of transducer elements in the ring area is connected to one signal line, and the signals in the group of transducer elements are bound together. Thereafter, an identical delay amount is given to the bound signals, and they are added to signals of a signal line to which a group of transducer elements in other ring area is connected, whereby phasing is performed. Accordingly, the number of signal lines (the number of channels) can be reduced to the number of the ring areas, and since it is sufficient for a delay circuit to be installed for each of the signal lines, the number of the delay circuits can be reduced as well.    [Patent document 1]    Japanese unexamined patent application publication No. 2005-34633    [Patent document 2]    Japanese unexamined patent application publication